Information storage apparatus for monitoring a number of defective sectors included in a zone so as to select a substitutional area from a different zone

Abstract

In an information storage apparatus, a substitution process for substitutionally storing information, when an error occurs in storing the information is prevented from being repeatedly performed with a substitutional area defined in the same recording zone, so that wasteful execution of the substitution process is prevented. The information storage apparatus stores information on a recording medium having a plurality of recording zones, each of the recording zones being divided into a plurality of sectors. A substitutional area is defined in each of the recording zones so as to substitutionally store information when an error occurs in storing the information. A defective sector detecting unit detects a defective sector in each of the recording zones. A control unit controls an operation for storing information so as to store the information, when a number of defective sectors included in a first one of the recording zones is greater than a predetermined value, in the substitutional area of a second one of the recording zones other than the first one of the recording zones in which the information is to be stored. The predetermined number is smaller than a maximum number of defective sectors includable in the substitutional area.

What is claimed is:  
     
       1. An information storage apparatus adapted to store information on a recording medium having a plurality of recording zones, each of the recording zones being divided into a plurality of sectors, a substitutional area being defined in each of the recording zones to substitutionally store information when an error occurs in storing the information, said information storage apparatus comprising: 
       a defective sector detecting unit detecting a defective sector in each of the recording zones; and  
       a control unit controlling an operation for storing information so as to store the information, when a number of defective sectors included in a first one of the recording zones is greater than a predetermined value, in the substitutional area of a second one of the recording zones other than the first one of the recording zones in which the information is to be stored;  
       wherein the predetermined number is smaller than a maximum number of defective sectors includable in the substitutional area.  
     
     
       2. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes a recording-zone defective sector detecting unit detecting a number of defective sectors included in the first one of the recording zones other than the substitutional area, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said recording-zone defective sector detecting unit is greater than the predetermined value. 
     
     
       3. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes a substitutional-area defective sector detecting unit detecting a number of defective sectors included in the substitutional area of the first one of the recording zones, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said substitutional-area detecting unit is greater than the predetermined value. 
     
     
       4. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes a track defective sector detecting unit detecting a number of defective sectors included in a single track of the first one of the recording zones, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said track defective sector detecting unit is greater than the predetermined value. 
     
     
       5. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes a single-access defective sector detecting unit detecting a number of defective sectors generated during a single access to the first one of the recording zones, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said single-access detecting unit is greater than the predetermined value. 
     
     
       6. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes a consecutive defective sector detecting unit detecting a number of defective sectors consecutively generated in the substitutional area of the first one of the recording zones, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said consecutive defective factor detecting unit is greater than the predetermined value. 
     
     
       7. The information storage apparatus as claimed in  claim 1 , wherein said defective sector detecting unit includes an initial defective sector detecting unit detecting a number of defective sectors included in the first one of the recording zones immediately after the recording medium is formatted, and said control unit stores the information, which is to be stored in the first one of the recording zones, in the substitutional area of the second one of the recording zones when the number of defective sectors detected by said initial defective sector detecting unit is greater than the predetermined value. 
     
     
       8. The information storage apparatus as claimed in  claim 1 , further comprising a medium-type detecting unit detecting a type of the recording medium, wherein said control unit sets the predetermined value in accordance with the type of the recording medium detected by said media-type detecting unit. 
     
     
       9. The information storage apparatus as claimed in  claim 1 , further comprising a temperature detecting unit detecting a temperature of atmosphere of the recording medium, wherein said control unit sets the predetermined value in accordance with the type of the recording medium detected by said temperature detecting unit. 
     
     
       10. The information storage apparatus as claimed in  claim 1 , further comprising a setting unit setting the predetermined value in accordance with an instruction supplied from an external apparatus.